Typical powder coating systems use a spray booth for powder overspray containment and recovery, one or more manual or automatic powder spray guns, and a powder coating material supply. Powder pumps are used to draw powder from the supply through associated pump hoses or suction tubes, and then to push the powder from the pumps through associated gun hoses to the spray guns in the spray booth. When it is desired to change the powder coating material, such as the type of powder, color, and so on, it is often necessary to completely purge the spray coating system of the prior powder material before the next powder material is used. This can involve purging the pump hoses, the pumps, the gun hoses and the spray guns.
Presently, each gun hose and associated spray gun are manually purged. Each gun hose is purged by individually disconnecting each gun hose from its pump and using a blow gun or wand to blow pressurized air through the gun hose and spray gun. After purge is complete, the gun hose is manually reconnected at one end to its spray gun and at its opposite end to a pump associated with the next powder supply to be used. While each hose/gun pair may take a few seconds to purge out, some coating systems use many guns and so the manual purging operation represents a significant time delay for powder change. This consequently results in costly downtime of the overall coating system.
For example, a bicycle manufacturer may want to sell white, black, red, blue, yellow and green bicycles. Such a manufacturer would need a separate supply, or hopper, for each color of powder. If bicycles were being painted red, for example, the hoses of the powder spray guns would be connected to powder pumps on the red power hopper so that red powdered paint would be supplied from the red powder hopper to all the spray guns. The powder pumps would typically be carried on the lid of the hopper and would travel with the hopper.
If, for example, the manufacturer next wanted to paint a run of bicycles blue, the red powder hopper would be disconnected from the hoses, each of the hoses and spray guns would be cleaned of any red colored powder, and then the hoses would be connected to the pumps on the blue powder hopper so that the blue powder could be supplied to the spray guns. In a system having twenty-four spray guns, for example, that means that all twenty-four hoses and spray guns would have to be individually cleaned during the color change process.